Fan coil thermostat with activity sensing

ABSTRACT

Fan coil thermostats can provide energy savings by, for example, not unnecessarily heating and/or cooling an unoccupied room or other space. Fan coil systems employing such a fan coil thermostat may be more energy efficient. A fan coil system may include a fan coil that is configured for fluid communication with a source of heated fluid and/or a source of cooled fluid, a valve that controls fluid flow through the fan coil, a fan that blows air across the fan coil and a fan coil thermostat. The fan coil thermostat may include a controller that implements a control algorithm that may include an unoccupied temperature setting. The controller may be programmed to permit a user to enter a user-chosen temperature setting. In response, the controller may initiate a timer, and may automatically return to the unoccupied temperature setting once the timer has expired.

TECHNICAL FIELD

The present disclosure pertains generally to thermostats and moreparticularly to thermostats adapted for use with fan coils.

BACKGROUND

A variety of buildings such as hotels, apartment buildings and the likeare heated and cooled using fan coil systems. In a fan coil system, aheat transfer fluid such as water is pumped or otherwise forced througha fan coil. A fan is used to blow air across the fan coil. If the heattransfer fluid was heated, heated air will blow out of the fan coilsystem. Conversely, if the heat transfer fluid was cooled, cool air willblow out of the fan coil system.

Like other HVAC systems, fan coil systems often consume significantamounts of energy. For many buildings, such as hotels and otherstructures, a number of rooms may, at any given time, be unoccupied. Asignificant amount of energy may be saved by controlling unoccupiedrooms or spaces to an energy savings setback temperature, rather than acomfort temperature.

SUMMARY

The present disclosure pertains to a fan coil thermostat that canprovide energy savings by, for example, not unnecessarily heating and/orcooling an unoccupied room or other space, while still providing comfortto the occupants when the room is occupied. Fan coil systems employingsuch a fan coil thermostat may be more energy efficient.

In an illustrative but non-limiting example, a fan coil thermostat maybe configured for use with a fan coil system. In some cases, the fancoil system may include a fan coil that is configured for fluidcommunication with a source of heated fluid and/or a source of cooledfluid, a valve that controls fluid flow through the fan coil, and a fanthat blows air across the fan coil.

The fan coil thermostat may include a controller that implements acontrol algorithm that is adapted to at least partially control one ormore components of the fan coil system, and that may include anunoccupied temperature setting. The fan coil thermostat may include atimer. A user interface may include one or more buttons and may beadapted to provide a signal to the controller when one or more of thebuttons are operated, thereby providing the controller with auser-chosen temperature setting as well as an indication of occupancy.In response, the controller may initiate a timer, and may automaticallyreturn to the unoccupied temperature setting once the timer expires.

The above summary is not intended to describe each disclosed embodimentor every implementation of the present invention. The Figures andDetailed Description that follow more particularly exemplify theseembodiments.

BRIEF DESCRIPTION OF THE FIGURES

The invention may be more completely understood in consideration of thefollowing detailed description of various embodiments of the inventionin connection with the accompanying drawings, in which:

FIG. 1 is a schematic view of an illustrative but non-limiting fan coilsystem;

FIG. 2 is a schematic view of an illustrative but non-limiting fan coilthermostat as may be used in the fan coil system of FIG. 1;

FIG. 3 is a front view of an illustrative embodiment of the fan coilthermostat of FIG. 2; and

FIG. 4 is a flow diagram showing an illustrative method that may becarried out using the fan coil system of FIG. 1.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and will be described in detail. It should be understood,however, that the intention is not to limit the invention to theparticular illustrative embodiments described. On the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention.

DESCRIPTION

The following description should be read with reference to the drawings,in which like elements in different drawings are numbered in likefashion. The drawings, which are not necessarily to scale, depictselected embodiments and are not intended to limit the scope of theinvention. Although examples of construction, dimensions, and materialsmay be illustrated for the various elements, those skilled in the artwill recognize that many of the examples provided have suitablealternatives that may be utilized.

FIG. 1 is a schematic view of an illustrative but non-limiting fan coilsystem 10. While fan coil system 10 is schematically shown as a two-pipefan coil system including a single supply line and a single return line,it will be appreciated that fan coil system 10 may instead be afour-pipe fan coil system having heated water supply and return lines aswell as cooled water supply and return lines. In some cases, a four-pipesystem may include a single fan coil while in other cases, a four-pipesystem may include two fan coils, with one dedicated to heated and onededicated to cooling. In a two-pipe fan coil system, the single supplyline may, for example, provide heated water during the heating seasonand may provide cooled water during the cooling season.

The illustrative fan coil system 10 includes a fan coil 12. Fan coil 12is a heat exchanger through which heated or cooled fluid flows. A fan 14blows air across fan coil 12 as schematically shown by arrows 16. Insome cases, fan 14 pulls ambient air from within the space and/or fromoutside the building. The ambient air is then heated or cooled by thefan coil 12 and provided into the space. In some cases, fan coil system10 may be disposed within a housing (not shown) having a first vent oropening upstream of fan 14 and a second vent or opening downstream offan coil 12. Fan 14 may pull air through the first vent or opening andthen exhaust the heated or cooled air through the second vent or openingand into the space. The components may be arranged either horizontallyor vertically within such a housing, as desired or perhaps as dictatedby space considerations.

In order to accommodate fluid flow through fan coil 12, fan coil system10 may include a supply line 18 and a return line 20. During the heatingseason, supply line 18 provides a source of heated fluid (such as water)from a suitable source such as a boiler or water heater, geothermaland/or the like. During the cooling season, supply line 18 may provide asource of cooled fluid (such as water) from a suitable source such as anevaporative cooling tower or the like.

In the illustrative embodiment, a valve 22 is disposed within supplyline 18, upstream of fan coil 12, in order to control fluid flow throughfan coil 12. In some cases, valve 22 may provide binary, i.e., on/offcontrol while in other cases it is contemplated that valve 22 may beconfigured to provide a plurality of flow rates into fan coil 12.

Fan coil system 10 may include a fan coil thermostat 24 that controlsoperation of valve 22 and/or operation of fan 14 in order to achieve adesired temperature level within a space that is conditioned by fan coilsystem 10. In some cases, while a fan coil thermostat 24 may be capableof storing a temperature setting such as an unoccupied temperaturesetting or perhaps a temporary temperature setting, the illustrative fancoil thermostat 24 is not configured or adapted to accommodate any otherprogrammed temperature setback information such as a temperature setbackschedule that pertains to differing temperature set points correspondingto particular periods of time during a day and/or week. In other words,the illustrative fan coil thermostat 24 may be adapted to operate onlyat the unoccupied temperature setting or temporarily at a user-chosentemperature setting. In other illustrative embodiments, the fan coilthermostat 24 may be a fully programmable thermostat that may include atemperature schedule that has programmable temperature set points forprogrammable periods of time during, for example, a day, days and/or aweek, as desired.

The illustrative fan coil thermostat 24 is better described with respectto FIG. 2. FIG. 2 schematically shows various components of anillustrative fan coil thermostat 24. Fan coil thermostat 24 includes auser interface 26 that may include a display 28 and a keypad 30. Display28 may be any suitable alphanumeric display medium that is capable ofdisplaying visually discernible information. In some cases, display 28may be a liquid crystal display (LCD), but this is not required. Keypad30 may include one or more individual electromechanical buttons such asan on/off button, a temperature up button, a temperature down button, afan speed up button, a fan speed down button, and the like. In somecases, it is contemplated that user interface 26 may be a touch screenLCD that encompasses the function of display 28 as well as keypad 30.That is, the buttons of keypad 30 may include, for example,electromechanical buttons, soft buttons, and/or touch regions on a touchscreen display, as desired.

The illustrative fan coil thermostat 24 also includes a controller 32.In some cases, controller 32 may implement a control algorithm that isadapted to at least partially control one or more components of fan coilsystem 10. The controller algorithm may also include an unoccupiedtemperature setting. In some cases, the unoccupied temperature settingmay be a temperature set point that is chosen to conserve energy. Thistemperature set point may include one or both of a heating temperatureset point and/or a cooling temperature set point. These temperature setpoints may, for example, be determined and set during installation offan coil thermostat 24, or may be determined and set subsequent toinstallation by a contractor or other person. In one example, anunoccupied heating temperature setting may be set to 62° F., and anunoccupied cooling temperature setting may be set to 85° F. Thesetemperatures, which are merely illustrative, represent temperatures thatmay be maintained by fan coil system 10 (FIG. 1) when a particular spaceis unoccupied.

Controller 32 may be adapted to provide information to and/or receiveinformation from user interface 26. Controller 32 may, for example,display a current temperature and/or a current temperature set point ondisplay 28. Other examples of information that may be provided bycontroller 32 include a current fan speed, equipment status (on/off),current time, and the like. Examples of information that may be receivedfrom keypad 28 may include changes in a temperature set point, changesin fan speed and/or status, and the like.

In some cases, fan coil themmostat 24 may include a memory block 34.Memory block 34 may be used to, for example, store one or moreunoccupied temperature settings, a current temperature set point, and/orprogramming that instructs controller 32 how to regulate valve 22(FIG. 1) and/or fan 14 (FIG. 1) in order to obtain and maintain aparticular temperature set point. In some cases, memory block 34 maystore, for example, the aforementioned control algorithm.

In some instances, fan coil thermostat 24 may include a sensor 36 thatprovides controller 32 with information pertaining to current sensedconditions within a space conditioned by fan coil system 10 (FIG. 1).Sensor 36 may be a temperature sensor, a humidity sensor and/or anyother suitable sensor, as desired. In some cases, sensor 36 may belocated internally to fan coil thermostat 24, although in someinstances, sensor 36 may instead be located remotely from fan coilthermostat 24.

Fan coil thermostat 24 may include a timer 38. In some cases, timer 38may be an electromechanical timer while in other instances timer 38 maybe an electronic timer or may even be manifested in programming run bycontroller 32. In some instances, if a user operates one or more buttonsof keypad 30, such as changing a temperature set point or perhapschanging the speed of fan 14 (FIG. 1), user interface 26 may provide asignal to controller 32 that provides controller 32 with a user-chosentemperature or perhaps a manually-selected fan speed setting. From this,controller 32 may also determine an indication of occupancy. i.e., thatsomeone is in the space. In response, controller 32 may temporarilychange the temperature set point from the unoccupied temperature settingto the user-chosen temperature setting, and/or change the fan speedsetting to a manually-selected fan speed setting. Controller 32 may alsoinitiate timer 38. The timer 38 may be adapted to expire at the end of apredetermined or other time period. Once the timer 38 expires, and insome cases absent any intervening detected interaction by the user viathe user interface 26, controller 32 may automatically change thetemperature set point back to the unoccupied temperature setting.

The predetermined time period of the timer 38 may be any suitable timeperiod. In some cases, the predetermined time period may have a lengthof about 3 hours, about 6 hours, about 12 hours, about 18 hours, about24 hours, or any other suitable length. In some instances, controller 32may be adapted to restart timer 38, and thus restart the predeterminedtime period, if controller 32 receives an additional signal via the userinterface 26, which would indicate occupancy of the space conditioned bythe fan coil system 10.

Alternatively, or in addition, it is contemplated that the timer 38 mayhave a length that is calculated to end at a particular time of day. Forexample, if fan coil thermostat 24 is installed in a hotel room, thetimer 38 may be adapted to expire at the checkout time of the hotel. Insome cases, the timer 38 may have a length that is calculated to end atthe particular day and the particular time that the guest is expected tocheck out. For example, if a guest is expected to check out in threedays at 11:00 AM, the timer 38 may be configured to expire on that dayand at that particular time. In any of these cases, this may provide theguest with the comfort that they desire, while helping to notunnecessarily heat and/or cool a particular room once the room becomesunoccupied.

FIG. 3 is a front view of an illustrative fan coil thermostat 40. Theillustrative fan coil thermostat 40 may be considered as an embodimentor perhaps as a particular example of fan coil thermostat 24 (FIG. 2).Fan coil thermostat 40 includes a housing 42 that may be formed of anysuitable material such as molded plastic. Fan coil thermostat 40 alsoincludes a display 44 that may be any suitable display such as an LCDdisplay.

The illustrative fan coil thermostat 40 includes several buttons thatmay be considered as examples of keypad 30 (FIG. 2). The buttonsillustrated are not to be considered as limiting in any way, but aremerely provided to show examples of buttons that may be included. Asillustrated, fan coil thermostat 40 includes a fan speed up button 46and a fan speed down button 48. In some cases, it is contemplated thatfan coil thermostat 40 may include a single fan speed button (not shown)that can be pressed repeatedly to step through the available fan speedsettings. In some instances, a slider button or even a rotary dial maybe provided to select a fan speed setting.

As illustrated, fan coil thermostat 40 includes a temperature up button50 and a temperature down button 52. A user may select and/or alter atemperature setting by pressing temperature up button 50 and/ortemperature down button 52, as appropriate. A power button 54 may alsobe provided. It is contemplated that fan coil thermostat 40 may insteadhave a touch screen LCD that provides the functionality of display 44 aswell as fan speed up button 46, fan speed down button 48, temperature upbutton 50, temperature down button 52, and power button 54. In somecases, the various buttons may be provided as touch regions on the touchscreen display.

FIG. 4 is a flow diagram that shows an illustrative method that may becarried out by fan coil thermostat 24 (FIG. 2) and/or fan coilthermostat 40 (FIG. 3). At block 56, controller 32 (FIG. 2) controlsfluid flow through fan coil 12 (FIG. 1) by controlling valve 22 (FIG. 1)and/or regulates a fan speed of fan 14 (FIG. 1) in accordance with anunoccupied temperature setting. At block 58, a temporary temperature setpoint is received from user interface 26 (FIG. 2), and then controller32 initiates timer 38 (FIG. 2) as shown at 60, which in some cases, mayinclude starting a countdown. The timer 38 may be adapted to expire atthe end of a predetermined or other time period. Controller 32 mayinstruct timer 38 to restart if, for example, another temperature setpoint is entered via user interface 26.

Control passes to block 62, where controller 32 (FIG. 2) controls fluidflow through fan coil 12 (FIG. 1) by controlling valve 22 (FIG. 1)and/or regulates a fan speed of fan 14 (FIG. 1) in accordance with thetemporary temperature setting. At block 64, controller 32 reverts backto the unoccupied temperature set point once timer 38 (FIG. 2) expires.

While the present disclosure has been described with respect toillustrative fan coil systems that include one or more pipes carryingheated water for heating and/or cooled water for cooling, it should benoted that the inventive concepts described herein are not limited tosuch systems. Some systems may be hybrid-type systems, with an A/Ccompressor for cooling and heated water for heating. Some systems may bethrough-the-wall systems, having one or more of a compressor for airconditioning, an electric or gas heating element for heating, and a heatpump. Fan coil thermostat 40 may, for example, be used with thesesystems as well as the systems described herein.

The present disclosure should not be considered limited to theparticular examples described above, but rather should be understood tocover all aspects of the disclosure as fairly set out in the attachedclaims. Various modifications, equivalent processes, as well as numerousstructures to which the present disclosure can be applicable will bereadily apparent to those of skill in the art to which the presentdisclosure is directed upon review of the instant specification.

We claim:
 1. A method of operating a fan coil system comprising a fancoil accommodating fluid flow therethrough and a fan configured to blowair across the fan coil, the method comprising: controlling fluid flowthrough the fan coil, regulating the fan speed, or controlling fluidflow through the fan coil and regulating the fan speed in accordancewith an unoccupied temperature set point; accepting a temporarytemperature set point by sensing activation of one or more temperatureset point buttons by a user; in response to accepting the temporarytemperature set point via sensing activation of one or more of thetemperature set point buttons, performing the following: initiating atimer in response to accepting the temporary temperature set point;controlling fluid flow through the fan coil, regulating the fan speed,or controlling fluid flow through the fan coil and regulating the fanspeed in accordance with the temporary set point; automaticallyreverting to the unoccupied temperature set point once the timerexpires, wherein controlling fluid flow through the fan coil, regulatingthe fan speed, or controlling fluid flow through the fan coil andregulating the fan speed only occurs in accordance with the unoccupiedtemperature set point or with the temporary set point and does not occurin accordance with a programmed schedule; and restarting the timer ifanother temporary temperature set point is accepted before the timerexpires.
 2. The method of claim 1, wherein the timer expires after atime period of about 12 hours.
 3. The method of claim 1, wherein thetimer expires after a time period of about 24 hours.
 4. A fan coilthermostat for use with a fan coil system that includes a fan coilaccommodating fluid flow therethrough and a fan configured to blow airacross the fan coil, the fan coil thermostat comprising: a userinterface comprising a display and one or more temperature set pointbuttons; a memory for storing an unoccupied temperature set point; acontroller operatively coupled to the memory and the one or moretemperature set point buttons, the controller configured to: control thefan coil system to control fluid flow through the fan coil, regulate thefan speed, or control fluid flow through the fan coil and regulate thefan speed in accordance with an unoccupied temperature set point; accepta temporary temperature set point via the one or more temperature setpoint buttons, and in response to accepting the temporary temperatureset point: initiate a timer; control the fan coil system to controlfluid flow through the fan coil, regulate the fan speed, or controlfluid flow through the fan coil and regulate the fan speed in accordancewith the temporary set point; automatically revert to controlling to theunoccupied temperature set point once the timer expires; and restart thetimer if another temporary temperature set point is accepted via the oneor more temperature set point buttons before the timer expires.
 5. Thefan coil thermostat of claim 4, wherein the timer expires after about 12hours.
 6. The fan coil thermostat of claim 4, wherein the timer expiresafter about 24 hours.
 7. The fan coil thermostat of claim 4, wherein thetimer is configured to expire at a predetermined time of day.
 8. The fancoil thermostat of claim 7, wherein the predetermined time of daycorresponds to a checkout time.
 9. The fan coil thermostat of claim 4,wherein the unoccupied temperature set point comprises a temperature setpoint chosen to conserve energy, the unoccupied temperature set pointdetermined and set by a contractor or other maintenance personnel.
 10. Afan coil thermostat for use with a fan coil system that includes a fancoil accommodating fluid flow therethrough and a fan configured to blowair across the fan coil, the fan coil thermostat comprising: acontroller implementing a control algorithm that is configured to causethe fan coil system to control fluid flow through the fan coil, regulatethe fan speed, or control fluid flow through the fan coil and regulatethe fan speed, in accordance with a temperature setting, the controlalgorithm defaults to controlling to an unoccupied temperature setting;a timer controlled by the controller; a user interface comprising one ormore temperature adjustment buttons for increasing or decreasing auser-chosen temperature setting, the user interface configured toprovide a signal to the controller when one or more of the one or moretemperature adjustment buttons are operated by a user, the signalproviding the controller with the user-chosen temperature setting andalso providing the controller with an indication of current occupancy;wherein, in response to the indication of current occupancy, thecontroller is configured to cause the fan coil system to temporarilycontrol fluid flow through the fan coil, regulate the fan speed, orcontrol fluid flow through the fan coil and regulate the fan speed, inaccordance with the user-chosen temperature setting rather than theunoccupied temperature setting and to initiate the timer, the controllerreturning to controlling the unoccupied temperature setting once thetimer expires; and the controller further configured to restart thetimer if a subsequent indication of current occupancy is received afterthe timer is initiated but before the timer expires.
 11. The fan coilthermostat of claim 10, wherein the timer expires after a period oftime, wherein the period of time is 3 hours or more.
 12. The fan coilthermostat of claim 10, wherein the timer expires after a period oftime, wherein the period of time is 12 hours or more.
 13. The fan coilthermostat of claim 10, wherein the timer expires after a period oftime, wherein the period of time is 18 hours or more.
 14. The fan coilthermostat of claim 10, wherein the timer is configured to expire at apredetermined time of day.
 15. The fan coil thermostat of claim 14wherein the predetermined time of day corresponds to a checkout time.16. The fan coil thermostat of claim 10, wherein the unoccupiedtemperature set point comprises a temperature set point chosen toconserve energy, the unoccupied temperature configured to be determinedand set by a contractor or other maintenance personnel.